Multiple element hydrokinetic torque converter



Jan. 5, 1965 M. G, GABRIEL 3,163,988

Filed June 13, 1963 INVENTOR.' /Vmfr//v @16W/a BY L Sym M. G. GABRIEL Jan. 5, 1965 MULTIPLE ELEMENT HYDROKINETIC TORQUE CONVERTER 5 Sheets-Sheet 2 Filed June 13, 1963 M. G. GABRIEL Jan. 5, 1965 MULTIPLE ELEMENT HYDROKINETIC TORQUE CONVERTER 5 Sheets-SheerI -3 Filed June 13, 1965 4 a mw WW V .f mvo/r YN NWML REQ United States Patent O 3,163,988 DULTPLE ELEMENT HYBRKENETEC TGRQUE CNVERTER Martin G. Gahriei, Dearborn, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation ci Delaware Filed June 13, 1963, Ser. No. 297,693 2 Claims. (Cl. titl-54) My invention relates generally to hydrokinetic torque transmitting mechanisms, and more particularly to a multiple element hydrokinetic torque converter having multiple stators that are arranged strategically to provide an increased torque multiplication for any givene speed ratio and improved coupling eiciency.

In a preferred form of my invention, I have provided a torque converter mechanism having three turbines connected together for rotation in unison and three stators situated in toroidal fluid ilow relationship in a torus circuit with the turbines and the converter impeller. One stator is situated at the exit section of each turbine. The third stator, which is located in the torus circuit at the exit region of the third turbine, functions to provide an optimum impeller entrance angle for the absolute iiuid ow velocity vector at this point in the circuit. This optimum entrance condition is maintained throughout the torque conversion range.

Provision may be made for allowing the stators to freewheel at separate speed ratios during operation in the torque conversion range. I contemplate that the third turbine, which is located at the impeller exit region, will freewheel at a relatively high speed ratio, whereas the other stators that precede it will freewheel at lower speed ratios.

The provision of an improved hydrokinetic torque converter mechanism of the type above set forth being a principal object of my invenion, it is a further object of my invention to provide a multiple element torque converter unit having multiple turbine numbers and multiple stator members wherein a positive torque contribution by each of the turbine members can be obtained throughout the entire speed ratio range without adversely influencing the absolute iiuid iiow velocity vector entrance conditions at the impeller entrance Vregion of the converter unit.

It is a further object of my invention to provide a multiple element hydrokinetic unit of the type above set forth wherein means are included for distributing turbine torque to a power output shaft through a simple clutch and brake arrangement thereby establishing a gearless infinitely variable torque ratio power transmitting path.

It is a further object of my invention to provide a mechanism of the type set forth in preceding objects wherein the clutch and brake arrangement includes a hill brake feature that permits braking torque to be developed under those conditions in which the turbines tend to overrun the impeller.

It is a further object of my invention to provide a mechanism as set forth in the preceding objects wherein the reverse torque reaction of the stators is utilized to establish a reverse drive condition.

For the purpose of describing more particularly the improvements of my invention, reference will be made to the accompanying drawings, wherein,

FIGURE 1 shows in cross sectional form an assembly view of my improved multiple element torque converter mechanism;

FIGURE 2 shows in schematic form a torque converter mechanism of the type shown in FIGURE 1 in combination with a clutch and brake system in a typical automotive vehicle drive line installation; and

FIGURE 3 is a vector representation of the velocity ice vectors of a particle of iluid as it traverses the torus circuit of the converter mechanism of FIGURE 1.

Referring first to FlGURE 1, the impeller shell is shown at 1G. It is formed with a generally toroidal shape and includes a hub 12 that is welded or otherwise secured to a sleeve shaft 14. This shaft may be mounted rotatably within a bearing opening formed in the stationary transmission housing structure.

The periphery of the shell 1t) is ianged at 16, and it may be bolted by means of bolts 18 to the periphery 2t) of a closure plate 22. In the structure shown, a spacer ring 24 is disposed between the periphery 16 and the periphery 20 although other arrangements also may be used.

A drive plate 26 is connected at its periphery to the periphery 20 of the plate Z2. The bolts 18 provide this connection.

The drive plate 26 can be connected in -a conventional fashion to the crankshaft of an internal combustion vehicle engine.

The plate 22 is formed with a. hub 23 which is provided with a pilot opening 30. A turbine hub 32 is journalled by means of bushings 34 within the opening 30. A suitable thrust washer 36 is situated between the hub 28 and the hub 32.

An inner impeller shroud 38 is secured at its periphery 49 to the interior of the shell 1t). It is secured also at 42 to the hub 12 of the shell 10. I contemplate that the connection between the shroud 38 and the shell 10 can be made by spot welding-or by any other suitable manufacturing technique.

An inner impeller shroud is shown at 44. Impeller blades 46 are secured between the shrouds 44 and 38 and cooperate therewith to define radial outflow passages. The connection between the blades 46 and the shrouds 38 and 44 can be established by forming suitable slots in the shrouds through which tabs formed on the margins of blades 46 are received. The tabs can be deformed tangentially to establish a locking condition between the blades and the shrouds.

Located at the fluid flow exit region of the impeller is a rst turbine generally identified by reference character 48. It includes an outer shroud in the form of a turbine ring 50 and an inner shroud 52. Disposed between the shrouds for turbine 48 are turbine blades S4. Blades 54 are pinned or otherwise secured to the irst turbine shrouds, suitable pins 56 being provided for this purpose. A web member 58 is formed integrally with shroud 52 and bolted or otherwise secured to another web member et?. Bolts 62 may be used for this purpose.

Web member' iideiines an outer shroud 64 for a third turbine identiiied generally lay reference character 66. This third turbine includes blades 68 disposed between shroud 64 and another shroud 7l). It is situated at a radially inward region of the toroidal fluid flow circuit ofthe converter mechanism.

Shroud 70 deiines a hub having an opening 72 which is splined to an externally splined adapter 74. Adapter 74 is held axially fast with respect to shroud 7G by snap rings 76 and 78. Adapter 74 is journalled upon a stationary sleeve shaft 80 by means of bushing 82. This shaft 80 is splined at 84 to a stator shaft 86 which may be connected in a fixed fashion to the stationary transmission housing.

Disposed at the ow exit region of the first turbine 4S is a iirst stator 88. This'includes an outer shroud 90, an inner shroud 92 and stator blades 94 disposed between the shrouds. Blades 94 can `be pinned or otherwise secured to shroud 92.

'I'he inner race 92 for the first stator 88 is splined at 96 to an externally splined race 98 of an overrunning clutch assembly. This assembly includes also an inner race 100 and rollers 102 situated between the races. One of the races can be cammed to permit locking action of the rollers to occur. This allows relative freewheeling motion of the races in one direction ybut inhibits relative lrotation in the opposite direction. The rollers 192 and the associated races are held axially fast by retainer plates 104 and 196. These in turn are held axially fast with respect to the outer race 92 -by snap rings 198 and 11i?.

Race 160 is pinned or otherwise positively connected to a first race 112 of a second stator 114. This stator 114 includes also a second race 116 and stator blades 118 disposed between the races.

Race 116 is in the form of a hub having a splined opening 120 which receives an externally splined race 122. Overrunning brake elements in the form of rollers or sprags are situated between race 122 and the stationary sleeve shaft 80. These are indicated by reference character 124. The overrunning brake assembly is held axially fast by means of snap rings 126 and 128 which prevent axial movement with respect to the race 115.

Spacer elements 136 and 132 are situated on either side of the overrunning brake elements 124i. Radial needle thrust bearings 134 are disposed between the spacer. elements 13S and the hub 32 of the second turbine.

Overrunning brake elements 124 inhibit rotation of the second stator 1Min one direction but accommodate freewheeling motion thereof in the opposite direction. Overrunning brake elements 124 thus establish a one-way torque delivery path to the stationary housing from each of the stators 88 and 114.

The fluid ow exit region of the first stator 88 is situated adjacent the entrance region of a second turbine 136. This turbine includes an outer shroud 138 and an inner shroud 14B. Second turbine blades 142 are situated between the shrouds and cooperate therewith to define radial inflow passages. The radially inward periphery of the shroud 138 is secured by rivets 144 to the hub 32. The turbines 48 and 136 are connected together for joint rotation by means of the element 50, as indicated. Element 50 is keyed by means of a dog and slot connection to outer shroud 138. This connection may comprise radially projecting elements 14o which may be welded or otherwise secured to the outer surface of shroud 138. These are received within slots 148 formed in the end of element 56.

A third stator is disposed between the uid ow exit region of the second turbine 66 and the impeller. It is indicated generally by reference character 150, and includes a first shroud 152 and a second shroud 154. Third stator blades 156 are disposed between the shrouds. Shroud 154 is formed with an internally splined opening 153 which receives an externally splined overrunning brake race 166. Rollers or sprags 162 are situated between race 16d and stationary sleeve shaft 80 to establish a one-way braking action between the stator 156 and the sleeve shaft 8G. It accommodates, however, overrunning freewheeling motion of the stator 150 during operation in the coupling range in the opposite direction.A

Disposed on either side of the overrunning brake elements 152 are spacer members 164 and 165. These are held axially fast by snap rings 16S and 170 within the shroud 154.

Radial needle bearings 172 anda thrust washer 174 accommodate the axial thrust acting upon the stator 152. Another radial needle bearing 176 is situated between adaptor 74 and the spacer element 164. In similar fashion, another radial needle bearing 178 is situated between adaptor 74 and the spacer element 132.

The .turbine hub 32 is splined at 189 to a driven turbine shaft 182. During oper-ation of the torque converter mechanism, engine torque is delivered to the impeller thereby establishing toroidal fluid ow circulation. Each of the turbines is adapted to transmit driving torque to the shaft 152. During operation in the lower speed ratios, each of the stators 4is prevented `from rotation by their respective overrunning brakes. When a speed ratio of approximately .40 is reached, however, the rst stator SS begins to freewheel thus establishing a first clutch point. As the speed ratio increases still further, the second stator continues to provide a change in the direction of the toroidal fluid how velocity vector. After a speed ratio of .6G is reached, however, the second stator freewheels through the action of its overrunning brake. Torque multiplication continues during subsequent increases in speed ratio until a clutch point of approximately .9 is achieved. At this time, the third stator 15? begins to freewheel. Thereafter, the converter ymechanism operates in a socalled coupling range at 1:1 torque ratio.

Referring next to FIGURE 2, l have illustrated a clutch and brake system that may be employed with a converter of the type described with reference to FIGURE l. The converter portion of the structure in FiGURE 2 is identied generally by reference character 184. The elements of the converter structure 184 that have counterpart elements in the construction of FIGURE l have been indicated by corresponding reference characters although primed notations have been added. In the construction of FIGURE 2 the turbines are connected to shaft 182 as in the previous embodiment, shaft 182 corresponding to shaft 182 as explained previously. The turbines are connected also to a second turbine shaft 136 which is iu the form of a sleeve shaft surrounding the stator shaft S6. Shaft 136 is secured to a turbine hub 1228 that in turn is connected to shroud 7d' of the third turbine 66.

Steeve shaft 186 is connected in 4turn to a reverse brake drum 1% around which is positioned a reverse brake band 192. Suitable iiuid pressure operated servo means may be provided for selectively applying and releasing the band 192. In this Way, the turbines can be held stationary or released.

Stator shaft 18e is connected to a brake drum 194 about which is disposed a hill brake band 196. This brake band may be applied to augment the hill braking capacity of the hydroldnetic mechanism by holding the stators stationary as the turbines overrun the impeller. The torque that then is transmitted from the turbines to the impeller and hence to the engine is supplemented by reverse action torque delivered through the medium of Ithe hydrolnnetic fiuid to the stators and hence to the stationary transmission housing.

Stator sleeve shaft 36' is connected to an inner race 198 of an overrunning coupling generally identiiied by reference character 2ili. Coupling 2G49 includes an outer race Zi that may be cammed to cooperate with rollers 224 situated between the races. Rollers .2534 will permit relative rotation of races in one direction, but will inhibit such rotation in the opposite direction.

Race 2t2 forms a part of a brake drum 2de about which is positioned a forward brake band 253. This band is applied during forward drive operation and functions to transmit stator reaction torque tothe stationary transmission housing. It may be applied and released by means of a suitable uid pressure operated servo. Brake band 196 may be operated in the same fashion with a separate fluid pressure opearted servo.

Drum 266 is drivably connected to power output shaft 21d through a selected engageable reverse friction clutch 212. This clutch is applied during reverse drive opera-tion as will be explained subsequently. Power output shaft 219 may be connected directly to shaft 1&2 through a selectively engageable forward drive friction clutch 214` During normal forward drive operation, the forward clutch 2143 is applied. The turbines arc effective to deliver turbine torque to the shaft 182' in the manner previously described, each turbine contributing a portion of the driving torque. The reverse torque reaction of the stators during operation of the converter in the torcye conversion range is distributed through shaft 86 and through overrun-ning coupling 26d to the forward brake band 25516.

Band S is applied to accommodate the torque reaction delivery to the stationary transmission housing.

To establish reverse drive operation, brake band 192 is applied and brake band 268y is released. Likewise the forward clutch 214, which was applied during forward drive operation, now is released.

To establish hill brake operation, the forward drive clutch 2M remains applied, and the hill brake band 1% is applied thereby anchoring the first and second stators to inhibit rotation thereof in either direction. This bypasses the overrunning coupling 20d. lf the output shaft then tends to overrun the power input shaft, a reaction torque will be applied to the stators and this in turn is delivered to the stationary transmission housing. The balance of the torque reaction, of course, is transmitted to the vehicle engine from the impeller. Eileotivc hill braking capacity of the hydroldnetic unit is magnified in this fashion.

Referring next to FIGURE 3, l have illustrated the velocity vectors for a particle ot' fluid as it traverses the torus circuit of the hydroliinetic torque converter unit during operation of the torque converter unit at various speed ratios. For purposes of this diagram, the blade elements have been illustrated in an unwrapped condition to dene a blade cascade. The normal torus ilow is in the direction of the horizontal arrow and the direction of rotation is downward as viewed in FIGURE 3. The fluid ltlow entrance blade angle Jfor the impeller blades 46 is designated by the symbol ,8. The blade exit angle is indicated by the symbol fy. The entrance blade angle for the turbine blades 54 is A1. The exit blade angle for blades 54 is indicated by the symbol B1. The entrance blade angle for the iirst stator is shown at A1 and the exit angle is shown at B1.

The blade entrance angle for the second turbine blades M2 is indicated by the symbol A2. The second turbine blade exit angle is shown at B2. The blade entrance angle for the second stator blades 5.18 is shown at A2' Vand the exit angle for the blades l is shown at B2.

The blade entrance angle for the third turbine blades 68 is shown at A3 and the third turbine blade exit angle is shown at B3.

The blade entrance angle for the third stator blades 156 is shown at A3 and the third stator exit angle is shown at B3'.

According to a principal feature of my invention, the geometry of tre blade elements and their strategic position within the torus circuit is sucn that a favorable entrance angle for the impeller blades 46 is achieved regardless of varying speed ratios. The symbol for speed ratio in the diagram o FIGURE 3 is a. The most desirable blade entrance angle for the impeller is one that will correspond to the angle of the absolute Huid flow velocity vector of a particle of iuid at the entrance region of the impell-er blades. This is indicated by the vector v1 in FIGURE 3. The normal tlow for that particle of uid at the entrance region of the impeller blades is indicated by the vec-tor f1 and the oW along the blades is shown at w1. The rotation vector due tothe rotation of the irnpeller blades is kshown by the vector u1. The vector v1 represents the vectorial sum of the vectors u1 w1 and f1. The angle of the absolute fluid llow velocity vector is shown at a.

During operation of the mechanism at any speed ratio less than the iinal coupling point, which may be approxi mately .9 speed ratio, the entrance vector at the impeller entrance region is determined by the conditions that exist at the tlow exit region of the third stator blades 156. The vectorial representation-oi a particle of duid at this point in the circuit includes the vectors F3 and the vector V3. This latter vector, of course, also is equal to the flow vector along the lade, namely W3.

The vector V3' is the absolute fluid liow velocity vector at the exit region of the third stator blades. The tangential component of the absolute duid ilow velocity vector at this point is shown S3.

The angle of the absolute fluid flow velocity vector is indicated by che symbol A3'. The angle A3' is slightly less than the angle a at low speed ratios and is slightly larger than the angle a at higher speed ratios. VThe blade angle is a compromise value that is somewhere between these two extremes, and this minimizes the degree of shock loss at this point in the torus circuit. The angle A3', however, does not deviate a great deal from the value of the angle a, and for all practical purposes the entrance angle for the impeller is always favorable for optimum converter performance.

The flow vectors for a particle of iluid at the exit region of the impeller also are illustrated in FIGURE 3. The absolute fluid iow velocity vector at this point is shown at vo. This is equal to the vectorial sum of the rotational vector un, the normal dow fo and the dow along the blade wo. The angle formed by the absolute duid ow velocity Vector is indicated at The tangential component of the absolute fluid dow velocity vector at the exit region of the impeller is shown at so.

The magnitude of the moment of momentum applied to the particle of fluid by the impeller as it traverses the bladed passages of the impeller is equal to the mass of that particle times the difference in the tangential cornponents of the absolute duid dow velocity vector times the diierence in the radii. This is a measure of the difference in the moments of momentum at the exit region of the third stator and the exit region of the impeller. It will be apparent that the moment of momentum ap plied to the particle of duid is of a substantial magnitude since the length of vector so is greater 'than the length of the vector S3. Also the operating radius of a particle of iiuid at the exit region of the impeller is much greater than the operating radius of a particle of duid at lthe exit region of the third stator.

As the torus flow traverses the bladed passages of the rst turbine, a change in the moment or" momentum is experienced. lts magnitude decreases which indicates that a positive driving torque is contributed by the first turbine.

The torque applied to the first turbine is determined by the difference in the moment of momentum of a .particle of fluid at the exit region of the rst turbine less the moment of momentum of a particle of fluid at the exit region of the impeller, the latter being equal, of course,v

to the moment of momentum at the entrance region of the rst turbine. At stall or zero speed ratio, the tangential component of the absolute Huid flow velocity vector is shown at S1. There is no rotational vector, of course. At this time the ilow along the blade and the absolute tluid flow velocity vector are indicated at W1 and V1 respectively. The angle formed by the absolute duid flow velocity vector is shown at A1. The direction of the vector S under zero speed ratio conditions `is opposite to the direction of vector so. lt is thus apparent that the change in the moment of momentum of the iluid as it traverses the rst turbine bladed passages is substantial Which indicates that a relatively large torque contribution is made by the rst turbine at low speed ratios.

As the speed of 'the first turbine increases, a rotational vector U1 is imparta-:dto the particle of fluid. At a speed of about .4, the absolute fluid how veiocity vector then will change direction as indicated in FGURE 3. The tangential component of the absolu'te fluid dow velocity vector now is in the same direction as the tangential component of the absolute fluid tlow velocity vector so. lt is shorter, however, which indicates that even at a `speed ratio of .4 a positive torque contribution is being made by the iirst turbine although it is of a reduced magnitude.

At any speed ratio above .4, the irst stator blade-s 94 are capable of redirecting the absolute fluid iiow. The angle of the absolute iluid ilow Velocity vector at the exit region of the iirst stator blades is shown at A1 and is greater than the angle A1 at any speed ratio less than .4. If the angle A1 becomes greater than the angle A1', the iirst stator blades will freewheel since the overrunning coupling elements 102 are incapable of accommodating torque delivery in a reverse direction.

The normal flow at the exit region of the tirst stator is shown at F1 and the liow along the blade is of equal magnitude and has the same direction as the absolute fluid ow velocity Vector. These vectors are shown at W1 and Vi. The tangential component of the absolute iluid ViloW Velocity vector is shown at S1.

As the particle of fluid traverses the second turbine bladed passages, the moment of momentum is decreased. The difference in the moment of momentum at the exit region of the blades 142 and the moment of momentum at the exit section of the preceding first stator blades is a measure of the torque contributed by the second turbine. A't zero speed ratio the absolute fluid tlow velocity vector at the exit region of the second turbine is shown by the vector V2. This is equal in magnitude and direction to the flow along the blade W2. The normal tiow is lshown at F2 and the angle formed with the absolute iiuid flow velocity vector is shown at A2. At zero speed ratio the tangential component of the absolute duid iiow velocity Vector F2 is in a direction that is opposite to the direction of the absolute uid ow velocity vector S1. Thus a deiinite reduction in the moment ot momentum of the iluid as it traverses the second turbine blades is apparent. The operating radius at the exit sec'tion of the second turbine blades, of course, is less than the operating radius at the exit section of the first stator blades, which also indicates that a reduction in the moment of momentum takes place. This evidences a positive driving torque.

The tangential component of the absolute lluid flow velocity vector increases as the speed ratio increases and changes direction. Until the vector S2 becomes equal in direction and magnitude to the direction and magnitude of the vector S1, a positive torque contribution will be established. Thus the second turbine will contribute torque even after the iirst coupling point of .4 speed ratio is reached.

The second stator blades liti redirect the fluid ilow that leaves the exit region of the second turbine blades. The ow vectors at the exit region ot' the stator blades 118 include the absolute Huid liow velocity vector V2 which is equal in direction of magnitude to the vector for the tiow along the blades W2'. The normal now is shown at F2 and the tangential component of the absolute fluid flow velocity vector is shown at S2. These vectors describe the entrance conditions for the third turbine blades 63. The vectors at stall for the third turbine blades GS-are shown in FIGURE 3 as well as the corresponding vectors at the clutch point of .9 speed ratio. At stall, the tangential component of the absolute Huid vtlow velocity vector V2 of the third turbine is in a direction that is opposite to the direction of rotation and is of a reduced magnitude. The angle of the absolute liuid flow velocity vector V3 is shown at A2. Thus a substantial reduction in the moment of momentum of the uid as it traverses the third turbine blades is experienced, which indicates a positive torque contribution. As the rotational vector U3 is imparted to the particle, the direction of the vector S3 reverses and its magnitude increases. Up until the time the second coupling point of a .6 speed ratio is achieved, the vector S3 is of a lesser length than the vector S2'. After the second clutch point of a .6 speed ratio is achieved, however, the third turbine still is capable of contributing a positive torque to the power output shaft since vector S3 will be of a lesser magnitude than the vector S2 for a particle of uid at the exit region of the blades 142. This condition will be maintained until the final coupling point is reached.

I am aware of a known, prior art, multiple turbine converter construction in which the discontinuities in the bladed passages defined by the converter blades occur at locations at which a change in the moment of momentum takes place during operation. This is in sharp contrast to my improved converter construction wherein the corresponding blade discontinuities occur at regions of constant maximum or minimum radii. Since this is true, no change in the moment of momentum occurs at these discontinuities, and etiiciency is improved accordingly. This characteristic is not shown or suggested by any prior art teachings.

I am aware also of a multiple element converter construction whicb includes plural turbines wherein the final turbine stage is located directly adjacent the entrance region of the impeller. A counterpart for stator is lacking. For purposes of comparison, it will be apparent that if the stator l5@ were to be removed, the absolute fluid liow velocity vector V3 would be the vector that is received by the entrance region of the impeller. Since the vector V3 at stall is substantially 90 out of phase with respect to the vector vi, the torque required to establish any given moment of momentum at the exit region of the irnpeller thus would be increased. This, of course, would reduce the stall speed, but it would reduce also the operating ehciency correspondingly. As the rotational vector U3 is applied to a particle of fluid at the exit region of the blades 63, the vector V3 would become substantially equal in magnitude and direction to the vector vi. This would occur at the higher speed ratios as indicated in FIGURE 3. Thus the impeller speed for any given engine torque would increase rapidly as the speed ratio increases. At any speed ratio less than the nal coupling point of .9, however, the vector so would be less than it would be if the stator blades 156 were in the circuit. Thus an augmentation in the tangential component of the absolute Huid iiow velocity will not occur unless the blades 156 are arranged as I have shown them.

In defining the structural characteristics of my irnproved converter, the claims recite separate turbine blade discontinuities that are situated within the toroidal circuit at a substantially constant maximum or minimum radius. The expression substantially constant radius, for purposes of interpreting the claims, shall mean having a very small deviation from an absolute, unchanging radius. Normal manufacturing tolerances and other slight deviations that might occur during actual construction of my improved converter are not deemed to be variations in radius.

Having thus described a preferred embodiment of my invention, what I claim and desire to secure by U.S. Letters Patent is:

l. A hydrokinetic torque converter mechanism comprising a bladed impeller, a plurality of bladed turbines and a plurality of bladed stators situated in toroidal liuid flow relationship in a common torus circuit, said bladed impeller being located at a radial outtiow region of said circuit, a first turbine located at a radially outward region of said circuit adjacent the ow exit section of said impeller, a lrst sta.or located at said radially outward region adjacent the flow exit section of said first turbine, a second turbine located at a radial inliow region of said circuit, the fluid ow path extending from the flow exit section of said impeller to the iow entrance section of said second turbine being at a substantially constant and maximum radius, a second stator and a third turbine located at a radially inward region of said circuit, said turbines being connected together for rotation in unison, and a third stator situated in said radially inward region between the flow exit section of said third turbine and the flow entrance section of said impeller, the fluid flow path extending from the ilow exit section of said second turbine to the flow entrance section of said impeller being at a substantially constant and minimum radius, said turbines forming a composite bladed torque transmitting assembly with two turbine blade discontinuities, one discontinuity being located at the portion of said outward region that is occupied by said iirst stator, and the second discontinuity being located at the portion of said inward region that is occupied by said second stator, each discontinuity being characterized by a substantially constant operating radius of the path of the mean toroidai iiuid now that passes through it.

2. A hydrokinetic torque converter mechanism cornprising a bladed impeller, a plurality ot bladed turbines and a plurality of bladed stators situated in toroidal fluid oW relationship in a common torus circuit, said bladed impeller being located at a radial outow region of said circuit, a first turbine located at a radially outward region of said circuit adjacent the flow exit section of said impeller, a first stator located at said radially out ward region adjacent the ow exit section of said rst turbine, the uid ow path extending from the ow exit section of said impeller to the ow entrance section of said second turbine being at a substantially constant and maximum radius, a second turbine located at a radial inow region of said circuit, a second stator and a third turbine located at a radially inward region of said circuit, said turbines being connected together for rotation in unison, a third stator situated vin said radially inward region between the ow em't section of said third turbine and the flow entrance section of said impeller, the fluid flow path extending from the flow exit section of said second turbine to the ow entrance section of said impeller being at a substantially constant and minimum radius, an overrunning coupling connection between said rst stator and said second stator, a second overrunning coupling connection between said second stator and a stationary portion of said mechanism whereby said rst and second stators are adapted to freewheel independently upon achieving the respective coupling points,

Vand a third overrunning coupling connection between said third stator and said secondary portion of said mechanism whereby a third coupling point can be achieved independently of the operation of said first and second stators, and turbines forming a composite bladed torque transmitting assembly with two turbine blade discontinuities, one discontinuity being located at the portion of said outward region that is occupied by said rst stator, and the second discontinuity being located at the portion of said inward region that is occupied by said second stator, each discontinuity being characterized by a substantially constant operating radius of the path of the mean toroidal iluid flow that passes through it.

References Cited bythe Examiner UNITED STATES PATENTS 2,762,196 l 9/56 Ullery 60-54 JULUS E. WEST, Primary Examiner. 

1. A HYDROKINETIC TORQUE CONVERTER MECHANISM COMPRISING A BLADED IMPELLER, A PLURALITY OF BLADED TURBINES AND A PLURALITY OF BLADED STATORS SITUATED IN TOROIDAL FLUID FLOW RELATIONSHIP IN A COMMON TORUS CIRCUIT, SAID BLADED IMPELLER BEING LOCATED AT A RADIAL OUTFLOW REGION OF SAID CIRCUIT, A FIRST TURBINE LOCATED AT A RADIALLY OUTWARD REGION OF SAID CIRCUIT ADJACENT THE FLOW EXIT SECTION OF SAID IMPELLER, A FIRST STATOR LOCATED AT SAID RADIALLY OUTWARD REGION ADJACENT THE FLOW EXIT SECTION OF SAID FIRST TURBINE, A SECOND TURBINE LOCATED AT A RADIAL INFLOW REGION OF SAID CIRCUIT, THE FLOW FLOW PATH EXTENDING FROM THE FLOW EXIT SECTION OF SAID IMPELLER TO THE FLOW ENTRANCE SECTION OF SAID SECOND TURBINE BEING AT A SUBSTANTIALLY CONSTANT AND MAXIMUM RADIUS, A SECOND STATOR AND A THIRD TURBINE LOCATED AT A RADIALLY INWARD REGION O SAID CIRCUIT, SAID TURBINES BEING CONNECTED TOGETHER FOR ROTATION IN UNISON, 